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					  MIXED TREATMENT COMPARISONS TO
    EVALUATE THE EFFECTIVENESS OF
   STRATEGIES FOR PREVENTING FIRE
 RELATED INJURIES IN CHILDREN WITHIN
              THE HOME
                 Pedro Saramago Goncalves
        PhD Student, Centre for Health Economics, University of York

 In collaboration with Professor Alex Sutton, Dr Nicola Cooper, Paula
Dhiman: University of Leicester & Professor Denise Kendrick: University
   of Nottingham. On behalf of the ‘Keeping Children Safe’ project.
                      OBJECTIVES

• To identify the most effective (i.e. “best”)
  strategy for increasing the ownership of fire-
  related safety equipment in households (smoke
  alarms, fire extinguishers, fire guards, safe storage of
  matches/lighters, fire escape plans).
METHODS: Mixed Treatment Comparisons
 • MTC methods (a generalisation of meta-analysis
   methods) allow comparisons of strategies not
   directly assessed within any individual primary
   study.
                               A
                 Trials 3,4               Trials 1,2

             B                No trials                C

  • MTC uses the totality of the evidence to define
    a network of evidence
      STAGES IN MTC


1
    •Find the evidence


2
    •Define the network


3
    •Synthesise the evidence
        1. FINDING THE EVIDENCE
• Updated Cochrane systematic review of home
  safety education +/- safety equipment for the
  prevention of home injuries in childhood and
  meta-analyses of studies comparing intervention
  to usual care (Kendrick et al 2007)
• Systematic review of reviews with data extraction
  from relevant primary studies not in meta-
  analyses in Cochrane review (e.g. smoke alarm
  education vs. smoke alarm education + free fitted
  alarm)
          2. DEFINING THE NETWORK
                                    5. Education + low
                       1 trial
2. Education                        cost/free equipment
                                    + fitting
                          1 trial
                                                          E.g.
           1 trial
                                               2 trials   Interventions
                                                          for increasing
3. Education + low    2 trials                            ownership of
                                    1. Usual care
cost/free equipment                                       functioning
                                                          smoke alarms
           1 trial
                             3 trials


4. Education + low
                        3 trials 6. Education + home
cost/free equipment
                                 inspection
+ home inspection
    3. SYNTHESISING THE EVIDENCE
• Mixed treatment random effects model with a
  binary outcome (have functioning equipment / do
  not have functioning equipment)
• Adjusted for clustering in cluster trials that did
  not in original analysis (ICCs estimated from
  individual studies/literature)
• Outcomes:
  – Odds ratio of each intervention compared to one
    another
  – Probability of each intervention being the best
         RESULTS: Probability intervention is the “best”
                                                Fire                     Matches/lighters   Fire escape
      Probability           Smoke alarms                   Fire guards
                                           extinguishers                  safe storage         plans
Usual care                     0.000          0.017          0.008            0.017            0.030

Education                      0.000                         0.126            0.025            0.144

Education + equipment          0.210                         0.630
Education + equipment
                                              0.063                                            0.477
(not related)
Education + equipment +
                               0.160          0.752          0.126            0.038
home inspection
Education + equipment
(not related) + home                          0.107
inspection
Education + equipment +
                                                             0.110
home inspection + fitting
Education + equipment +
                               0.120                                          0.920
fitting
Education + home
                               0.510          0.030
inspection
Community campaigns                           0.031                                            0.349
     RESULTS: Odds Ratios versus standard care

    OR versus                                                                                       Matches/lighters
                            Smoke alarms            Fire extinguishers          Fire guards                                Fire escape plans
  standard care                                                                                      (safe storage)

Education                  1.049 (0.14 to 3.944)                            3.136 (0.081 to 15.62) 3.804 (0.09 to 14.2)   4.66 (0.163 to 28.34)

Education + equipment     4.901 (0.821 to 16.57)                            10.84 (0.326 to 64.6)

Education + equipment
                                                   1.773 (0.081 to 8.977)                                                 17.82 (0.093 to 94.07)
(not related)
Education + equipment +
                          5.862 (1.182 to 20.5) 11.06 (0.465 to 66.94) 2.403 (0.092 to 14.25) 1.244 (0.225 to 4.175)
home inspection
Education + equipment
(not related) + home                               2.525 (0.036 to 19.09)
inspection
Education + equipment +
                          3.449 (0.537 to 12.24)                            2.795 (0.061 to 13.72) 4127 (0.579 to 9299)
fitting
Education + home
                          14.21 (0.82 to 73.89) 1.215 (0.07 to 5.706)
inspection

Community campaigns                                1.097 (0.024 to 5.262)                                                 5.268 (0.167 to 25.97)
                       DISCUSSION
• Mixed Treatment Comparison Methods allow a coherent
  analysis of the totality of the evidence
• Major assumption of the approach:
   – The intervention effect estimated by the BC trials would be the
     same as the intervention effect estimated by the AC and AB trials
     if they had included B and C arms etc.
   – Violated if factors interact with intervention effects and these
     factors imbalanced across interventions (e.g. social group of study
     participants etc.)
• Quality/validity of studies ignored
   – As for standard meta-analysis, difficult to incorporate
• Small number of studies for most comparisons
• Results from these analyses are to be used in decision
  modelling to ascertain cost-effectiveness of the different
  interventions
                 CONCLUSIONS

• Results from the MTC show that more intensive
  interventions are generally estimated to be more
  effective (i.e. with the best strategies usually
  offering free or low cost equipment)
• The best strategies varies across equipment types
  – may partly be due to limitations in the data
• Further studies needed to increase precision of
  estimates and distinguish most effective
  components of interventions
    References and contact details
• References:
        Kendrick, D., Coupland, C., Mulvaney, C., Simpson, J. Smith, S.J., Sutton, A., Watson,
  M., Woods, A. Home safety education and provision of safety equipment for injury
  prevention. Cochrane Database of Systematic Reviews 2007, CD005014.

         Caldwell DM, Gibb DM, Ades AE. Validity of indirect comparisons in meta-analysis. The
  Lancet. 2007;369:270-1.

       Sutton, A.J., Ades, A.E., Cooper, N.J., Abrams, K.R. Use of indirect and mixed treatment
  comparisons for technology assessment. Pharmacoeconomics 2008: 26:753-767.



• Contact details:
         prsg500@york.ac.uk

  This study was funded by the National Institute for Health Research (NIHR) under its Programme Grants
  for Applied Research funding scheme (RP-PG-0407-10231).The views expressed are those of the author(s)
  and not necessarily those of the NHS, the NIHR or the Department of Health.

				
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